A footwear article is provided. The footwear article includes a shoe sole. The shoe sole includes a crosslinked foam polyolefin elastomer having a density less than 0.88 g/cm.sup.3, the crosslinked foam polyolefin elastomer including: a silane-grafted polyolefin elastomer, a silane-grafted olefin block copolymer, a polyolefin elastomer (POE), an olefin block copolymer (OBC), or a combination thereof; an ethylene vinyl acetate (EVA) copolymer; a crosslinker; a condensation catalyst; and a foaming agent. The shoe sole exhibits a compression set of from about 1.0% to about 50.0%, as measured according to ASTM D 395 (48 hrs @ 50° C.).

An expandable thermoplastic resin particle including a polymer obtained by a process including polymerizing monomers including 60 to 80 parts by weight of α-methylstyrene and 40 to 20 parts by weight of acrylonitrile. A content of residual monomeric components in the expandable thermoplastic resin particle is not more than 0.5% by weight. When an expanded mold article is produced from the expandable thermoplastic resin particle at an expansion ratio of 10 times, foam cells in a cross section of the expanded mold article have an average chord length of from 20 μm to 60 μm.

An expandable poly methyl methacrylate particle including a polymer, which is obtained by a process including polymerizing monomers including 100 parts by weight of an acrylic monomer and from 0.05 to 0.15 parts by weight of a polyfunctional monomer. The acrylic monomer includes 90% to 98% by weight of methyl methacrylate and 2% to 10% by weight of an C.sub.2-8 alkyl acrylate, relative to a total weight of the methyl methacrylate and the C.sub.2-8 alkyl acrylate.

An expandable poly methyl methacrylate particle including a polymer, which is obtained by a process including polymerizing monomers including 100 parts by weight of an acrylic monomer and from 0.05 to 0.15 parts by weight of a polyfunctional monomer. The acrylic monomer includes 90% to 98% by weight of methyl methacrylate and 2% to 10% by weight of an C.sub.2-8 alkyl acrylate, relative to a total weight of the methyl methacrylate and the C.sub.2-8 alkyl acrylate.

An expanded molded article comprising a fused body of expanded particles including a non-crosslinked olefin-based elastomer and not including a mineral oil, the expanded molded article having a density of 0.015 to 0.5 g/cm.sup.3 and a compression set of 25% or less.

An expanded molded article comprising a fused body of expanded particles including a non-crosslinked olefin-based elastomer and not including a mineral oil, the expanded molded article having a density of 0.015 to 0.5 g/cm.sup.3 and a compression set of 25% or less.

Amide-based elastomer expanded particles comprising, as a base resin, a non-crosslinked amide-based elastomer having a Shore D hardness of 65 or less, and having an average cell diameter of 20 to 250 μm.

The present disclosure provides a foam bead. The foam bead contains at least one of the following components: (A) a block composite; and/or (B) a crystalline block composite. The present disclosure also provides a sintered foam structure formed from a composition comprising at least one of the following components: (A) a block composite; and/or (B) a crystalline block composite.

The present disclosure provides a foam bead. The foam bead contains at least one of the following components: (A) a block composite; and/or (B) a crystalline block composite. The present disclosure also provides a sintered foam structure formed from a composition comprising at least one of the following components: (A) a block composite; and/or (B) a crystalline block composite.

Composite resin particles comprising 50 to 800 parts by mass of a polystyrene-based resin with respect to 100 parts by mass of a polyolefin-based resin, wherein: when transmission electron microscope (TEM) images obtained by photographing cross-sections of the composite resin particles using a TEM at a magnification of 1,000 are subjected to a binarization processing and areas in the obtained binarized images which correspond to a cross-sectional area of 437.584 μm.sup.2 of the composite resin particles are subjected to image analysis, the polystyrene-based resin satisfies the following requirements: (1) the number of dispersed particles is 180 or more; (2) the maximum of the areas of dispersed particles is 200 μm.sup.2 or less; and (3) the coefficient of variation in dispersion is 100% or more, and the composite resin particles exhibit an inner morphology that includes a mixture of sea-island structure regions and co-continuous structure regions.